Mercyful Fate, Sacramentum, Therion, Necrophobic, Gorguts, Enslaved, and Autopsy should be added, IMO. Possibly Averse Sefira, Ildjarn/Sort Vokter, and Dismember, as well. I would add The Chasm, although I know we'll never agree on that one.

I'd personally remove Nuclear Assault, Exodus, Monstrosity, Carnage, Nihilist, Belial, Napalm Death, and the entire Metalcore section. All of those bands (aside from Napalm Death and the metalcore bands) are great, but not up to the standards of the rest of that list. Possibly remove Demigod, Impaled Nazarene (sorry Finland!), Iron Maiden, and Summoning as well.

Don't add anything to the A-list. Instead, raise the bar of all lists - A, B, and C - and redefine some of these bands as B grade. The A-list is the music that so greatly encapsulates/enhances the Metal Spirit that Metal music as a whole would be lesser for its absence.